Means and method of perforating deep wells



Feb. 4, 1936. M HMNE 2,029,478

MEANS AND METHOD OF PERFORATING DEEP WELLS Filed Oct. 3, 1934 IN VEIV T OR Patented Feb. 4, 1936 PATENT OFFICE 2,029,478 MEANS AND METHOD OF PEBFORATING DEEP WELLS Marcul w. mines, Long mil, can, assign!!! to 'l'echnicralt Engineering (20110., Los Angeles,

Calif, a corporation Application October 3, 1934, Serial No. 746,674

7 The present invention is a method and means for increasing the efiiciency' oi submerged 81mfire, and relates to well casing perforations and similar operations wherein projectiles are discharged to perforate or penetrate steel, cement or other material submerged in'liquid.

The objects of. my invention include: The provision of a method and means for decreasing the resistance 01' liquid, surrounding a gun body, to progress therethrough of projectiles, by gasifying said liquid or otherwise releasing bubbles of air or gas in said liquid so that said liquid will be compressible sufiiciently to let it displace as the projectile moves through it.

In the drawing; Figure 1 is a partial sectional partial elevational view of my apparatus disposed within a liquid filled well casing; and Fig ure 2 is a transverse sectional view thereof through 11-11 of Figure 1.

Referring to the drawing, the numeral l indicates a well casing into which is lowered on a cable 2 a gun body 3.

Body 3 is bored and tapped at 4 to receive removable breech-blocks 6 into which are threaded at 'l removable barrels 8.

In the bores of barrels I are projectiles 9 to which are spot-welded discs ll. Said discs serve as a retard for projectiles 9 and as a seal against hydrostatic pressure of liquid l2 in casing I. When the discs are compressed by barrels 8, they seal combustion chambers in which are shells ll closed at both ends by wads l6. Thermo-electric elements I! extend through the shells l6 and the ends thereof are secured to contacts extending through the wads I6. One or said contacts in each shell presses against a pin II the lead of which is in contact with a spring dip I9 insulated at 2| from the gun body 3.

A wire 22 leads from clip l9 upward through a bore 23 in the gun body 3 and through cable 2 to a control switch at the mouth of the well.

When said control switch (not shown) is closed current from any suitable source, at the mouth of the well passes through insulated wire 22 to clip l9, through pin l8, to thermal element and gun body 3, thence through spring centering devices 24 to casing I.

The current, so introduced, energizes each of elements ll which are embedded in explosive 26 causing same to explode, shearing disc II and driving projectile 9 through the liquid l2, casing l and causing it to penetrate the surrounding formation.

The lower end of body 8 is bored and tapped at 26 to receive the threaded end or a pipe 21 surrounding casing.

9 Claims. (01. 81188) closed at the bottom by a cap 28 thereon.

Pipe 21 serves as a container for a gas-releasing agent, indicated at 29, which may be carbon dioxide, 002, or any chemical reagent capable of generating and disseminating gas at a pressure sufiicient to overbalance hydrostatic pressure of the drilling fluid I2.

I have found that commercial dry ice" is well adapted to this use. Just before the gun body 3 is lowered in casing I, the tubular container 21 is removed from the body 3 and filled with dry ice. It ordinarily requires about ten minutes of time to lower the gun to the level to be perforated. 1

Temperature change causes the dry ice to volatilize, escaping gas filling a chamber 3| in the gun body. Accumulations of pressure in said chamber unseats check valves 32 which open outwardly in passages 33 which bleed chamber 3| and discharge into fiutings 34 which are quadrilaterally disposed on the periphery of gun body 3. These grooves are positioned directly beneath the projectile bores in gun barrels 8 and serve to direct bubbles 29 of gas in upward travel past said bores.

I claim:

1. The combination with a submergible gun adapted to be fired while submerged; of a chamber connected with said gun said chamber containing a quantity of a compressible medium under pressure suificient to fiow from said chamber against the pressure of the liquid in which the gun is submerged; and means for discharging said medium into the region of gun-fire.

2. A submerged firing gun comprising; a gun body, means for discharging projectiles therefrom; and a container depending from said gun body and adapted to contain a compressible medium under pressure in excess of the liquid threaded .therearound; and means for discharging said medium into the region traversed by said projectiles.

3. A method of firing gun type well casing perforators while submerged in a liquid within a well casing, characterized by: creating an upwardly flowing gaseous jacket around the casing perforator and firing projectiles laterally from the peri'orator through the gaseous jacket and 4. A method of firing gun type well casing perforators while submerged in a liquid within a well casing, characterized by: increasing the compressibility oi the well fluid by introducing a gas therein below the casing periorator. 66

5. Amethodotiiringguntypewellcasing perrorators while submerged in a liquid within a well casing. characterized by: generating a gas at a point below the casing pertorator, and introducing the gas so generated into the well fluid to increase its compressibility.

6. The method or firing well casing perforators of the type having a plurality oi laterally directed gun units, characterized by: submerging the gun within a liquid filled well casing; introducing into the liquid below the gun a. train of gaseous bubbles in such a manner that they flow past the muzzles oi the several gun units to increase the compressibility or the surrounding liquid; then firing said gun units.

7. The method of minimizing excessive pressures within a liquid filled well casing during perforation thereof by gun fire,- characterized by: introducing into the liquid below the region of I apaaue with a gas to absorb the shock or such discharge.

9. A gun type well casing perforator adapted to be submerged in a well casing containing an incompressible 'fiuid and fired therein; and

. means for permeating the fluid with a compressibie medium to cushion or dampen the pressure surge created in the fluid upon firing the perforator.

MARCUS vW. HAINES. 

